Along with Thomas Alva Edison invented the light bulb, the light source produced by the electric power lights up the night, and also the civilization of mankind. With this kind of artificial light source, the human is able to take advantage of the time at night, which thus further led to the development of science, technology and education. In the research field about the impact of a light source on circadian stimulus (CS), Yasukouchi discovered the light source with high color temperature at night can more inhibit the secretion of melatonin than a light source with low color temperature. Next, since 2001, Branard has studied the relationship between the human eyes and the biological effects, so as to further reveal the relationship between the light source and the secretion of melatonin and the biological influences, which can be expressed by FIG. 1 “The relationship curve between a light source and the corresponding circadian stimulus” (2001, Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor). The further studies point out different wavelengths (400 nm-550 nm) of a light source have different influences on CS. Therefore, by judging the influence extent of a light source on human CS, a light source used for night or daytime should be different ones respectively with different appropriate spectral composition so as to provide appropriate artificial lighting sources.